Electric furnace.



No. 682,088. Patentnd Sent. 3. I90I.

F. A. KJELLIN. ELECTRIC FURIIACE.

(Avnlienm :und In. la, 1001.) (lo Model.)

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YUNITED STATES PATENT OFFICE.-

FREDRIK ADOLF IIJELLIN, OF GYSINGE, SWEDEN.

ELECTRIC FU RNACE.

SPECIFICATION forming part of Letters Patent N o. 682,088, dated September 3, 1901.

Application filed March 13, 1901. Serial No. 50,976. (No model.)

lTo @ZZ whom it may concern:

Be it known that I, FREDRIK ADoLn KJEL- LIN, engineer, of Gysinge, in the county of Gestrikland, Kingdom of Sweden, have invented certain Improvements in ElectricFurhaces; and I do hereby declare the nature of my invention and in what manner the same is to be performed to be particularly described and ascertained in and by the following stateinent'.

Forsmelting or heating ores, metals, and the like furnaces have already been employed in which an electric current sufficient for the smelting of the ore or of the metals is induced in the charge by means of alternating currents produced in a coil surroundingr the furnace, which incloses a core of iron or of other magnetic material.

The object ofI my invention is to arrange the induction-coils in such furnaces in such a manner that they become cheaper and more eifective.

In order that my invention may be readily understood and carried into eifect, I will describe the same fully with reference to the accompanying drawings, in which- Figure I is a vertical section of a furnace embodying my invention, and Fig. 2 a section on line C/ C' thereof. y

Referring to the drawings, a is the refractory walls of the furnace, and C an annular groove or chamber for the reception of the charge to be smelted or heated.

c is a central channel surrounding the iron core cl. In furnaces of this kind as heretofore constructed the conductor connected to the generator for the electric current is coiled around the furnace; but according to my invention the conductor is coiled directly on the core d, and thus inside the smelting or heating chamber. By arranging the cond uctor in such a manner the advantage is attained-that the length, and thus the cost as well as the loss of. energy at the passage of the current, is considerably reduced. The surface of the wall between the induction-coil and the chamber G also becomes considerably smaller than in the case when the` conductor is placed outside said chamber C, in consequence whereof also the quantity of heat transmitted from the furnace to said conductor becomes smaller. The larger diameter the furnace possesses the larger is the area between the induction-coil and the chamber' C (at the same thickness of the wall) when the coil is placed outside the furnace, and the number of the lines of force which escape between the coil and the chamber() also becomes larger, in consequence whereof the self-induction is increased. By such an arrangement the eect thus is diminished as the diameter of the furnace increases.

In furnaces arranged according'to my irivention the space between the induction-coil and the chamber C may thus be smaller than when the coil is placed outside said furnacechamber C, in consequence whereof the effect becomes considerably greater than in the furnaces as heretofore constructed, and in addition my improved furnaces may also be made in considerably larger sizes than has been possible heretofore.

I-Iaving now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is-- An electrical furnace comprising an annular furnace-chamber, a core dof magnetic material arranged centrally thereof and an induction-coil arranged around said core and within the annular furnace-chamber and connected to an alternating-current generator for the purpose of by said coil to induce currents in the charge of the annular chamber, suicient for the smelting of charge therein.

In witness whereof I have hereunto set my hand in presence of two witnesses.

FREDRIK ADoLF KJELLIN.

Witnesses:

JOHN EDBERG, BIRGER LINDT. 

